I think they're both at fault but William may be slightly worse as he just sits back and lets his brother take the fall for all of this like he has done multiple times in their lives. We have seen he has a temper. He could very easily come out and apologise for his actions, admit his mistakes and be the proper example a true king would be. He doesn't have to do much, just one statement and then he never has to say anything again.
If Diana was alive she'd probably knock their heads together.
The entire documentary was a little disappointing if I'm honest. I was expecting real bombshells but I guess there are none. I'm still on the fence with it all and not really on anyone's side.